:root{font:16px/1.5 system-ui;color:#182936;background:#f3f7f8}*{box-sizing:border-box}main{max-width:760px;margin:auto;padding:24px}header{display:flex;align-items:center;justify-content:space-between}h1{font-size:26px}button{background:#154b61;color:white;border:0;border-radius:10px;padding:12px 20px;cursor:pointer}button:disabled{opacity:.6}#messages{min-height:180px;max-height:58vh;overflow:auto}.user,.assistant{white-space:pre-wrap;border-radius:12px;padding:16px;background:white}.user{background:#dcecf2;margin-left:10%}textarea{display:block;width:100%;min-height:80px;padding:12px;margin:8px 0;border:1px solid #abbfc6;border-radius:10px;font:inherit}small{display:block;margin-top:16px;color:#4c6571}